Display device and control method

ABSTRACT

Provided is a display device including an imaging unit that captures a moving image in a predetermined range in an image display direction, a moving body detection unit that detects whether or not a moving body is present in a predetermined range in the image display direction, an image analysis unit that analyzes the moving image captured by the imaging unit to detect whether or not a face is present, and a power control unit that controls power consumption with different patterns according to a plurality of modes that are set by combining whether or not the face detected by the image analysis unit is present and whether or not the moving body detected by the detection unit is present.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.13/124,987 filed Jun. 29, 2011, which is a National Stage ofPCT/JP2010/064372 filed Aug. 25, 2010, and claims priority to JapanesePatent Application No. 2009-205997 filed Sep. 7, 2009. The entirecontents of each of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a display device and a control method.

BACKGROUND ART

According to the survey of Japan Electronics and Information TechnologyIndustries Association (JEITA), an average television viewing time perday is 4.5 hours. However, it has been found that a television is notviewed continuously during the 4.5 hours due to recent changes inlifestyle.

For example, when viewing the television while preparing to go to workor school in the morning or while having a meal, a screen of thetelevision may not be continuously viewed. Further, when a program thatis sufficient by an input from a voice such as a weather forecast isbeing broadcasted, viewers may not look at the screen, or may have aconversation with another person. Then, a behavior of beginning to viewthe screen of the television again due to an interesting keyword runningin topical news or sports news is frequently done.

That is, as a representative television viewing form, the television isturned on instead of a clock in the morning, and “simultaneous viewing”of listening to a sound of the television while operating a personalcomputer (PC) at night has recently increased. When “simultaneousviewing” is performed, power is unnecessarily expended in a state inwhich the screen of the television is turned on. For this reason, adisplay device in which an imaging device is installed around thetelevision screen, and power save control optimal for a viewing state isexecuted by performing face detection through the image device andanalyzing a user's viewing state has been proposed.

SUMMARY OF INVENTION Technical Problem

However, in the power save control using only face detection, there hasbeen a problem in that even when it is desired to continuously view thedisplay device, for example, when it is difficult to detect the user'sface due to an installation environment of the television or when theuser looks away during a certain time period, it is ultimately judgedthat viewing, that is, the face, is not present, and thus the display isturned off. Further, since the face detection process requires arelatively long image processing time compared to moving body detection,in an environment in which a computation rate or a resource isrestricted, there has been a problem in that a response from when theuser comes in front of the display device for viewing to when the imageis displayed is delayed.

Further, there is a display device in which power save control isperformed by detecting a moving body or the user's action through animaging device or a pyroelectric infrared element and analyzing theuser's viewing state. However, there has been a problem in that when theuser keeps viewing without moving, it is erroneously judged that theuser is not present, and the screen display is turned off. In order toavoid such a malfunction, it is necessary to increase a time until thepower save control starts, which in turn deteriorates a power saveeffect.

The present invention is made in view of the above-mentioned issues, andaims to provide a display device and a control method which are noveland improved, and which are capable of efficiently executing the powersave control with a high degree of accuracy by combining the user'smoving body detection and face detection.

Solution to Problem

According to an aspect of the present invention in order to achieve theabove-mentioned object, there is provided a display device including animaging unit that captures a moving image in a predetermined range in animage display direction, a moving body detection unit that detectswhether or not a moving body is present in a predetermined range in theimage display direction, an image analysis unit that analyzes the movingimage captured by the imaging unit to detect whether or not a face ispresent, and a power control unit that controls power consumption withdifferent patterns according to a plurality of modes that are set bycombining whether or not the face detected by the image analysis unit ispresent and whether or not the moving body detected by the detectionunit is present.

The power control unit may have a first mode in which power consumptionof the display device is controlled only according to whether or not theface detected by the image analysis unit is present, and when the imageanalysis unit has not been able to detect the presence of the faceduring a predetermined time, power consumption decreases.

The power control unit may have a second mode in which power consumptionof the display device is controlled using whether or not the facedetected by the image analysis unit is present and whether or not themoving body detected by the moving body detection unit is present, powerconsumption decreases up to a predetermined level when the imageanalysis unit has not been able to detect the presence of the faceduring a first predetermined time, and, after the decrease, powerconsumption further decreases when the moving body detection unit hasnot been able to detect the presence of the moving body during a secondpredetermined time.

The power control unit may have a third mode in which power consumptionis controlled using whether or not the face detected by the imageanalysis unit is present and whether or not the moving body detected bythe moving body detection unit is present, and when the image analysisunit has not been able to detect the presence of the face during apredetermined time and the moving body detection unit has not been ableto detect the presence of the moving body during the predetermined time,power consumption decreases.

The power control unit may control power consumption of the displaydevice by increasing or decreasing brightness of a display panel thatdisplay an image.

The power control unit may control power consumption of the displaydevice by increasing or decreasing a sound volume of a speaker thatdisplay a voice.

The power control unit may control power consumption of the displaydevice by controlling an operation of a circuitry configured to increasean image quality of a display image.

The display device may further include a notification unit that notifiesthat control of power consumption is stopped when the power control unitstops control of power consumption of the display device.

The image analysis unit may specify an individual through analysis onthe moving image captured by the imaging unit, and the power controlunit may automatically select the mode corresponding to the individualspecified by the image analysis unit.

The power control unit may automatically select the mode correspondingto the details of content to be displayed.

The power control unit may not start control of power consumption of thedisplay device until the face or the moving body is first detected afterpower is turned on.

According to another aspect of the present invention in order to achievethe above-mentioned object, there is provided a control method includingan imaging step of capturing a moving image in a predetermined range inan image display direction, a moving body detection step of detectingwhether or not a moving body is present in a predetermined range in theimage display direction, a face detection step of analyzing the capturedmoving image to detect whether or not a face is present, and a powercontrol step of controlling power consumption with different patternsaccording to a plurality of modes by combining whether or not the faceis present and whether or not the moving body is present.

Advantageous Effects of Invention

As described above, according to the present invention, a display deviceand a control method which are novel and improved, and which are capableof efficiently executing the power save control with a high degree ofaccuracy by combining the user's moving body detection and facedetection can be provided.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an explanation diagram for explaining an appearance of animage display device according to an embodiment of the presentinvention.

FIG. 2 is an explanation diagram illustrating a configuration of theimage display device 100 according to an embodiment of the presentinvention.

FIG. 3 is an explanation diagram for explaining a configuration of acontrol unit 110.

FIG. 4 is a flowchart illustrating an example of a power save processperformed by the image display device 100 according to an embodiment ofthe present invention.

FIG. 5 is an explanation diagram for explaining a power save operationin respective power save modes in the image display device 100 accordingto an embodiment of the present invention.

FIG. 6 is a flowchart illustrating a power save operation of the imagedisplay device 100.

FIG. 7 is a flowchart illustrating a power save operation of the imagedisplay device 100.

FIG. 8 is a flowchart illustrating a power save operation of the imagedisplay device 100.

FIG. 9 is an explanation diagram illustrating an operation example ofthe image display device 100 when a power mode is intentionally beingsuppressed.

FIG. 10 is an explanation diagram illustrating an operation example ofthe image display device 100 when a power mode is intentionally beingsuppressed.

DESCRIPTION OF EMBODIMENTS

Hereinafter, preferred embodiments of the present invention will bedescribed in detail with reference to the appended drawings. Note that,in this specification and the drawings, elements that have substantiallythe same function and structure are denoted with the same referencesigns, and repeated explanation is omitted.

Further, a description will be made in the following order:

<1. Embodiment of the Present Invention>

[1-1. Configuration of Image Display Device]

[1-2. Configuration of Control Unit]

[1-3. Power Save Process]

<2. Summary>

1. EMBODIMENT OF THE PRESENT INVENTION

[1-1. Configuration of Image Display Device]

First, a configuration of an image display device according to anembodiment of the present invention will be described. FIG. 1 is anexplanation diagram for explaining an appearance of an image displaydevice 100 according to an embodiment of the present invention. FIG. 1is a front view in which the image display device 100 is viewed from thefront. An appearance of the image display device 100 according to anembodiment of the present invention will be described below withreference to FIG. 1.

As illustrated in FIG. 1, the image display device 100 according to anembodiment of the present invention includes an imaging unit 104, whichcaptures a moving image, disposed in an upper-central part and left andright central parts of a display panel 102 that displays a still imageor a moving image. The imaging unit 104 captures the moving image in adirection in which the image display device 100 displays the still imageor the moving image through the display panel 102. The image displaydevice 100 according to the present embodiment analyzes an imagecaptured by the imaging unit 104 and detects a user's face reflected onthe image. The image display device 100 is characterized in that itsinternal operation state changes depending on whether or not the user'sface is included in the image captured by the imaging unit 104.

Further, the image display device 100 according to an embodiment of thepresent invention includes a sensor 106 disposed in a lower central partof the display panel 102. The sensor 106 detects whether or not a personis present in front of the image display device 100. The image displaydevice 100 is also characterized in that its internal operation statechanges depending on whether or not a person is present in front of theimage display device 100.

Further, the image display device 100 according to an embodiment of thepresent invention includes a light emitting diode (LED) 109. The LED 109notifies the user of a status of the image display device 100 through alighting status or an emission color.

Further, in the image display device 100 illustrated in FIG. 1, theimaging unit 104 that captures the moving image is disposed at threepositions around the display panel 102 of the image. It should beunderstood that in the present invention, an image input position atwhich the moving image is captured is not limited to the example. Forexample, a device separate from the image display device 100 may bedisposed, the corresponding device may be connected with the imagedisplay device 100, and the moving picture may be captured by thecorresponding device. Further, it should be understood that the numberof image input units is not limited to three, and two or fewer or fouror more image input units may be disposed to capture an image. Further,it should be understood that the number of the sensors 106 is notlimited to one, and two or more sensors may be disposed to detect thepresence of a person.

Further, although not shown in FIG. 1, the image display device 100 mayfurther include a signal reception unit that can receive a controlsignal from a remote controller (not shown) in an infrared ray manner, awireless manner, or the like.

The appearance of the image display device 100 according to anembodiment of the present invention has been described above withreference to FIG. 1. Next, a configuration of the image display device100 according to an embodiment of the present invention will bedescribed.

FIG. 2 is an explanation view illustrating a configuration of the imagedisplay device 100 according to an embodiment of the present invention.A configuration of the image display device 100 according to anembodiment of the present invention will be described below withreference to FIG. 2.

As illustrated in FIG. 2, the image display device 100 according to anembodiment of the present invention includes the display panel 102, theimaging unit 104, the sensor 106, a speaker 108, and a control unit 110.

The control unit 110 includes an image input unit 112, an imageprocessing unit 114, a viewing state analysis unit 116, a viewing staterecording unit 118, a system optimization processing unit 120, and asystem control unit 122.

The display panel 102 displays a still image or a moving image based ona panel drive signal. In the present embodiment, the display panel 102displays the still image or the moving image through a liquid crystal.Of course, it should be understood that the present invention is notlimited to the example. The display panel 102 may display the stillimage or the moving image by a display device of a light-emitting typesuch as an organic electroluminescence (EL).

The imaging unit 104 is disposed in the upper central part and the leftand right central parts of the display panel 102 that displays the stillimage or the moving image as described above. When the panel drivesignal is supplied to the display panel 102 and the moving image isdisplayed on the display panel 102, the imaging unit 104 acquires themoving image in a direction in which the image display device 100displays the moving image through the display panel 102. The imagingunit 104 may capture the moving image by a charge coupled device (CCD)sensor or a complementary metal oxide semiconductor (CMOS) sensor. Themoving image captured by the imaging unit 104 is transmitted to thecontrol unit 110.

The sensor 106 is displayed in the lower central part of the displaypanel 102 that displays the still image or the moving image as describedabove. The sensor 106 detects whether or not a person is present infront of the image display device 100. Further, when a person is presentin front of the image display device 100, the sensor 106 can detect thedistance between the image display device 100 and the person. Thedetection result and the distance information obtained by the sensor 106are transmitted to the control unit 110. The speaker 108 outputs a voicebased on a voice output signal.

The control unit 110 controls an operation of the respective componentsof the image display device 100. The respective components of thecontrol unit 110 will be described below.

The image input unit 112 receives the moving image captured by theimaging unit 104. The moving image received through the image input unit112 is transmitted to the image processing unit 114 and used for imageprocessing performed by the image processing unit 114.

The image processing unit 114 is an example of an image analysis unit ofthe present invention and executes a variety of image processing on themoving image, which is captured by the imaging unit 104, received fromthe image input unit 112. The image processing executed by the imageprocessing unit 114 includes a detection process of a moving bodyincluded in the moving image captured by the imaging unit 104, adetection process of the number of people included in the moving image,and a detection process of a face and a facial expression included inthe moving image. A result of a variety of image processing performed bythe image processing unit 114 is transmitted to the viewing stateanalysis unit 116 and used for analysis on the presence of a person whois viewing the image display device 100 or a state of a person who isviewing the image display device 100.

For example, the image processing unit 114 may use a technique disclosedin Japanese Patent Application Laid-Open (JP-A) Nos. 2007-65766 and2005-44330 for the face detection process of detecting the face includedin the image. The face detection process will be simply described below.

In order to detect the user's face from the image, the position of theface, the size of the face, and a direction of the face in the suppliedimage are detected, respectively. When the position and the size of theface are detected, a face image part can be cut from the image. Featureparts (facial feature positions) of the face such as an eyebrow, an eye,a neck, a nose, and a mouse are detected based on the cut face image andinformation of the direction of the face. The facial feature positionsmay be detected by detecting the feature positions, for example, using atechnique called active appearance models (AAM).

When the facial feature positions are detected, a local feature quantityis calculated on each of the detected facial feature positions. Thelocal feature quantity is calculated, and the calculated local featurequantity is stored in conjunction with the face image, and thus the facecan be distinguished from the image captured by the imaging unit 104. Asthe face distinguishing method, for example, a technique disclosed inJP-A Nos. 2007-65766 and 2005-44330 may be used, and thus a detaileddescription thereof will be omitted. Further, it can be judged based onthe face image or the facial feature positions whether a face appearingin the supplied image is a man or a woman or whether a face appearing inthe supplied image is an adult or a child. Further, since faceinformation is previously recorded, it is possible to search for aperson appearing in the supplied image from recorded faces and specifyan individual.

The viewing state analysis unit 116 receives the result of the variousimage processing performed by the image processing unit 114 and thedetection result and the distance information obtained by detection ofthe sensor 106. The viewing state analysis unit 116 analyzes thepresence or a state of a person who is viewing the image displayed bythe image display device 100 using the result of the various imageprocessing performed by the image processing unit 114 and the detectionresult and the distance information obtained by detection of the sensor106. Since the viewing state analysis unit 116 analyzes the presence ofa person or a state of a viewer, the image display device 100 candecrease brightness of the display panel 102 or control the direction ofthe display panel 102 depending on whether or not a person who isviewing the image display device 100 is present. An analysis result ofthe analysis process performed by the viewing state analysis unit 116 istransmitted to the viewing state recording unit 118 and the systemoptimization processing unit 120.

Further, the viewing state analysis unit 116 can detect the moving bodybased on the detection result and the distance information obtained bydetection of the sensor 106, but when the distance between the sensor106 and the moving body is equal to or more than a predetermineddistance, the moving body can be excluded from a detection target.

The viewing state recording unit 118 records the analysis resultobtained by the analysis process performed by the viewing state analysisunit 116. The analysis result of the viewing state analysis unit 116recorded in the viewing state recording unit 118 is used for a systemoptimization process in the system optimization processing unit 120.Further, the analysis result of the viewing state analysis unit 116recorded in the viewing state recording unit 118 may be transmitted toan external information collection server 200.

The system optimization processing unit 120 is an example of a powercontrol unit of the present invention. The system optimizationprocessing unit 120 calculates system control information for executingthe system optimization process on the respective components of theimage display device 100 using the analysis result obtained by theanalysis process of the viewing state analysis unit 116. The systemoptimization process on the respective components of the image displaydevice 100 includes power control of the image display device 100,brightness control of the display panel 102, direction control of thedisplay panel 102, display content control of the display panel 102,sound volume control of a voice output from the speaker 108, andoperation control of a circuitry (not shown) configured to increase theimage quality of the moving image displayed on the display panel 102.

As the circuitry configured to increase the image quality of the movingimage displayed on the display panel 102, for example, a speedincreasing circuit that increases a frame rate twice, three times, orthe like may be used. Power consumption of the image display device 100may be controlled by stopping a part or all of a circuit operation ofthe circuitry configured to increase the image quality of the movingimage such as the speed increasing circuit.

The image display device 100 can execute a power save process based onthe system control information calculated by the system optimizationprocessing unit 120. The system control information calculated by thesystem optimization processing unit 120 is transmitted to the systemcontrol unit 122.

Further, the image display device 100 according to the presentembodiment executes a power save operation according to a plurality ofpower save modes which will be described later. In each power save mode,the power save operation is executed based on the system controlinformation that is created, by the system optimization processing unit120, to have a different pattern according to the analysis result of theviewing state analysis unit 116.

The system control unit 122 executes the system optimization process onthe respective components of the image display device 100 based on thesystem control information calculated by the system optimizationprocessing unit 120. Specifically, the system control unit 122 executesbrightness control of the display panel 102, direction control of thedisplay panel 102, display content control of the display panel 102, andsound volume control of the voice output from the speaker 108 based onthe system control information calculated by the system optimizationprocessing unit 120.

A configuration of the image display device 100 according to anembodiment of the present invention has been described above withreference to FIG. 2. As described above, the image display device 100according to an embodiment of the present invention analyzes the user'sviewing state through the imaging unit 104 and the sensor 106. In theconventional art, the imaging process is performed by the imaging unit104, and the user's viewing state is analyzed only through the facedetection process that judges whether or not a face is included in theimage captured by the imaging unit 104. However, when the user's viewingstate is analyzed only through the face detection process, there hasbeen a problem in that even when it is desired to continuously view thedisplay device, for example, when it is difficult to detect the user'sface or when the user looks away during a certain time period, it isultimately judged that viewing is not present, and thus the display isturned off. Further, since the face detection process requires arelatively long image processing time compared to the moving bodydetection process using the sensor or the like, in an environment inwhich a computation rate or a resource is restricted, a response fromwhen the user comes in front of the display device for viewing to whenthe image is displayed has been delayed.

Meanwhile, there is a display device in which power save control isperformed by detecting the moving body or the user's action through apyroelectric infrared element or other sensors and analyzing the user'sviewing state. However, there has been a problem in that when the userkeeps viewing without moving, it is judged that the user is not present,and thus the screen display is turned off. In order to avoid such amalfunction, it is necessary to increase a time until the power savecontrol starts, which in turn deteriorates a power save effect.

The image display device 100 according to an embodiment of the presentinvention combines the face detection process on the image captured bythe imaging unit 104 and the moving body detection process performed bythe sensor 106. Thus, the user's viewing state can be more effectivelyanalyzed.

Next, a configuration of the control unit 110 included in the imagedisplay device 100 according to an embodiment of the present inventionwill be described in detail.

[1-2. Configuration of Control Unit]

FIG. 3 is an explanation view for explaining a configuration of thecontrol unit 110 included in the image display device 100 according toan embodiment of the present invention. Particularly, FIG. 3 illustratesconfigurations of the viewing state analysis unit 116 and the systemoptimization processing unit 120 among the components included in thecontrol unit 110. The configurations of the viewing state analysis unit116 and the system optimization processing unit 120 will be describedbelow with reference to FIG. 3.

As illustrated in FIG. 3, the viewing state analysis unit 116 includes auser viewing state analysis unit 132 and a user motion analysis unit134. The system optimization processing unit 120 includes a paneloptimization processing calculation unit 142 and a speaker optimizationprocessing calculation unit 144.

The user viewing state analysis unit 132 receives the result of thevarious image processing performed by the image processing unit 114, andthe detection result and the distance information obtained by detectionof the sensor 106. The user viewing state analysis unit 132 detectswhether or not a person who is viewing the image display device 100 ispresent, and a direction or a size of a face of a person who is viewingthe image display device 100 using the result of the various imageprocessing performed by the image processing unit 114, and the detectionresult and the distance information obtained by detection of the sensor106.

The user motion analysis unit 134 receives the result of the variousimage processing performed by the image processing unit 114, and thedetection result and the distance information obtained by detection ofthe sensor 106. The user motion analysis unit 134 analyzes whether ornot a person who is viewing the image display device 100 is present,based on time-series or special state or record of the user's motion,using the result of the various image processing performed by the imageprocessing unit 114, and the detection result and the distanceinformation obtained by detection of the sensor 106.

Here, the image processing unit 114 transmits the captured image, facedetection information (for example, information such as centralcoordinates [a1,b1], the size of a face [w1,h1], and a direction of aface [i1]) of each user who is using the image display device 100 in thecaptured image, and moving body information (for example, informationsuch as central coordinates [c1,d1], the size of a facial area [s1]) tothe viewing state analysis unit 116. The viewing state analysis unit 116performs the analysis process on whether or not a person who is viewingthe image display device 100 is present using the information receivedfrom the image processing unit 114 through the user viewing stateanalysis unit 132 and the user motion analysis unit 134.

The panel optimization processing calculation unit 142 calculates aprocess (a power save implementation process) capable of implementingoptimum power save in the display panel 102 using the result of theanalysis process performed by the user viewing state analysis unit 132and the user motion analysis unit 134. For example, the process capableof implementing optimum power save in the display panel 102 may includea process of controlling power consumption by increasing or decreasingbrightness of the display panel 102 according to whether or a person whois viewing the image display device 100 is present and a time in which aperson who is viewing the image display device 100 is not present, orcontrolling power consumption by increasing or decreasing the soundvolume of the voice output from the speaker 106. The power saveimplementation process calculated by the panel optimization processingcalculation unit 142 is transmitted to the system control unit 122 andused in the power save process of the display panel 102.

The speaker optimization processing calculation unit 144 calculates aprocess (a power save implementation process) capable of implementingoptimum power save in the speaker 108 using the result of the analysisprocess performed by the user viewing state analysis unit 132 and theuser motion analysis unit 134. For example, the process capable ofimplementing optimum power save in the speaker 108 may include a processof controlling a sound volume of the speaker 108 according to whether ora person who is viewing the image display device 100 is present and atime in which a person who is viewing the image display device 100 isnot present. The power save implementation process calculated by thespeaker optimization processing calculation unit 144 is transmitted tothe system control unit 122 and used in the power save process of thespeaker 108.

Further, for calculation of the power wave implementation process in thesystem optimization processing unit 120, an optimization processingeffect calculation unit 152 may be used. The optimization processingeffect calculation unit 152 calculates control information for theoptimum power save process corresponding to the user's viewing stateusing the analysis result of the viewing state analysis unit 116 and thecalculation result of the power save implementation process performed bythe system optimization processing unit 120.

The configuration of the control unit 110 included in the image displaydevice 100 according to an embodiment of the present invention has beendescribed with reference to FIG. 3. Next, the power save processperformed by the image display device 100 according to an embodiment ofthe present invention will be described.

[1-3. Power Save Process]

FIG. 4 is a flowchart illustrating the power save process performed bythe image display device 100 according to an embodiment of the presentinvention. The power save process performed by the image display device100 according to an embodiment of the present invention will bedescribed below with reference to FIG. 4.

The flowchart illustrated in FIG. 4 illustrates an example of atransition process to a mode (a power save mode) of suppressing powerconsumption of the image display device 100. A transition process to thepower save mode by the image display device 100 according to an exampleof the present invention will be described below in detail. When theimage display device 100 is powered on, the system optimizationprocessing unit 120 sets a control flag to one (1) (step S101). Thecontrol flag is a flag for deciding whether or not the power save modeis to be executed in the image display device 100. The power save modeis not executed when the flag is 1, but when the flag is zero (0), thepower save mode is executed. The viewing state analysis unit 116performs the face detection process and the moving body detectionprocess to judge whether or not a person who is viewing the imagedisplay device 100 is present (step S102).

The viewing state analysis unit 116 judges whether or not the presenceof a person who is viewing the image display device 100 has beendetected as a result of the face detection process and the moving bodydetection process of step S102 (step S103). When it is judged in stepS103 that the viewing state analysis unit 116 has detected the presenceof a person who is viewing the image display device 100, the systemoptimization processing unit 120 sets the control flag to 0 (step S104).However, when it is judged in step S103 that the viewing state analysisunit 116 has not detected the presence of a person who is viewing theimage display device 100, the control flag remains as 1.

Subsequently, it is judged whether or not the user has performed anoperation on the image display device 100 through the remote controllerfor operating the image display device 100 (step S105). The operationjudgment may be executed by the viewing state analysis unit 116.

When it is judged in step S105 that the user has performed an operationon the image display device 100 through the remote controller,information of a final operation time retained in the image displaydevice 100 is set to a current time (step S106). Setting the informationof the final operation time to the current time may be performed, forexample, by the viewing state analysis unit 116.

When information of the final operation time retained in the imagedisplay device 100 is set to the current time in step S106, the systemoptimization processing unit 120 releases the power save mode (stepS107).

However, when it is judged in step S105 that the user has not performedan operation on the image display device 100 through the remotecontroller, step S106 and step S107 are skipped.

Subsequently, the system optimization processing unit 120 judges whetheror not a power save mode start condition is satisfied (step S108). Thepower save mode start condition depends on the power save modedesignated by the user. An example of the power save mode startcondition in the image display device 100 according to an embodiment ofthe present invention will be described below, but it should beunderstood that the number of power save modes and the power save modestart condition of each power save mode are not limited to the example.

The image display device 100 according to an embodiment of the presentinvention has three kinds of power save modes including “High,”“Medium,” and “Low.” The system optimization processing unit 120calculates the system control information corresponding to each powersave mode, and the system control unit 122 executes a variety of controlbased on the calculated system control information. Thus, powerconsumption of the respective components of the image display device 100can be controlled with different patterns.

“High” is a power save mode in which when the viewing state analysisunit 116 has not recognized the face during a specific time period,transition to a power save operation of suppressing power consumption isperformed.

“Medium” is a power save mode in which when the viewing state analysisunit 116 has not recognized the face during a specific time period,transition to a power save operation of suppressing power consumption isperformed, and when the viewing state analysis unit 116 has notrecognized the face and the moving body during a specific time period,transition to a power save operation of suppressing power consumption isfurther performed.

“Low” is a power save mode in which when the viewing state analysis unit116 has not recognized the face and the moving body during a specifictime period, transition to a power save operation of suppressing powerconsumption is performed.

FIG. 5 is an explanation diagram for explaining the power save operationin the respective power save modes in the image display device 100according to an embodiment of the present invention. A graph illustratedin the uppermost row of FIG. 5 represents patterns of face detection andmoving body detection chronologically. In the other graphs of FIG. 5, ahorizontal axis denotes time, and a vertical axis denotes powerconsumption.

As illustrated in FIG. 5, when the power save mode is “High,” if theviewing state analysis unit 116 cannot recognize the face during aspecific time (for example, between 3 seconds and 10 seconds), powerconsumption is steadily suppressed, for example, by decreasing thebrightness of the display panel 102 or decreasing the sound volume ofthe speaker 108. However, when the viewing state analysis unit 116 canrecognize the face or when an operation on the image display device 100has been performed by the remote controller, the power save mode isreleased.

Further, when the power save mode is “Middle,” if the viewing stateanalysis unit 116 cannot recognize the face during a specific time (forexample, between 10 seconds and 30 seconds), power consumption issteadily suppressed up to about half, for example, by decreasing thebrightness of the display panel 102 or decreasing the sound volume ofthe speaker 108. Further, if the viewing state analysis unit 116 cannotrecognize the face and the moving body during a specific time (forexample, between 1 minute and 3 minutes), power consumption is furthersuppressed, for example, by decreasing the brightness of the displaypanel 102 or decreasing the sound volume of the speaker 108. However,when the viewing state analysis unit 116 can recognize the face or whenan operation on the image display device 100 has been performed by theremote controller, the power save mode is released.

Further, when the power save mode is “Low,” if the viewing stateanalysis unit 116 cannot recognize the face and the moving body during aspecific time (for example, between 3 minutes and 10 minutes), powerconsumption is steadily suppressed, for example, by decreasing thebrightness of the display panel 102 or decreasing the sound volume ofthe speaker 108. However, when the viewing state analysis unit 116 canrecognize the face or when an operation on the image display device 100has been performed by the remote controller, the power save mode isreleased.

FIG. 5 illustrates the power save operation in the respective power savemodes using two patterns of face detection and moving body detection. Apattern illustrated in a middle column of FIG. 5 illustrates a case inwhich the moving body is not detected after the face has not beendetected, the moving body is detected, and the face is detected afterthe detection. The pattern is referred to as “pattern 1.” Further, apattern illustrated at the right of FIG. 5 illustrates a case in whichthe face is detected again after the face had not been detected, theface is not detected again, the moving body is not detected again, theface is first detected, and then the moving body is detected. Thepattern is referred to as “pattern 2.”

If the power save mode is “High,” since transition to the power savemode is performed only according to whether or not the face is present,a power save operation illustrated in a graph of a second step from thetop of FIG. 5 is performed on each of the case of pattern 1 and the caseof pattern 2. If the power save mode is “Medium,” since powerconsumption is suppressed by first performing transition to the powersave mode according to whether or not the face is present and thenfurther suppressing power consumption according to whether or not themoving body is present, a power save operation illustrated in a graph ofa third step from the top of FIG. 5 is performed on each of the case ofpattern 1 and the case of pattern 2. If the power save mode is “Low,”since power consumption is suppressed by first performing transition tothe power save mode according to whether or not the face and the movingbody are present, a power save operation illustrated in a graph of afourth step from the top of FIG. 5 is performed on each of the case ofpattern 1 and the case of pattern 2.

When the system optimization processing unit 120 judges that the powersave mode start condition is satisfied in step S108, the systemoptimization processing unit 120 judges whether or not the control flagis 0 (step S109).

When the system optimization processing unit 120 judges that the controlflag is 0 in step S109, the system optimization processing unit 120judges whether or not a time obtained by subtracting the final operationtime set in step S106 from the current time has exceeded a specific time(step S110). For example, in the case in which the power save mode ofthe image display device 100 is set to “High,” the system optimizationprocessing unit 120 judges whether or not the time obtained bysubtracting the final operation time set in step S106 from the currenttime has exceeded 10 seconds.

When the system optimization processing unit 120 judges that the timeobtained by subtracting the final operation time set in step S106 fromthe current time has exceeded the specific time in step S110, the imagedisplay device 100 starts the power save mode (step S111). For example,in the case in which the power save mode of the image display device 100is set to “High,” if the time obtained by subtracting the finaloperation time set in step S106 from the current time has exceeded 10seconds, the image display device 100 starts the power save mode, anddecreases the brightness of the display panel 102 or decreases the soundvolume of the speaker 108 to steadily suppress power consumption.

After transition to the power save mode is performed in step S111, whenthe system optimization processing unit 120 judges that the power savemode start condition is not satisfied in step S108, when the systemoptimization processing unit 120 judges that the control flag is not 0in step S109, or when the system optimization processing unit 120 judgesthat a time obtained by subtracting the final operation time from thecurrent time has not exceeded the specific time in step S110, it isjudged whether or not an operation of the image display device 100 hasbeen finished, for example, because power is turned off (step S112). Ifthe operation of the image display device 100 has been finished, theprocess is finished as is. However, if the operation of the imagedisplay device 100 has not been finished, the process returns to stepS102, and execution of the face detection process and the moving bodydetection process is continued by the viewing state analysis unit 116.

The power save process performed by the image display device 100according to an embodiment of the present invention has been describedabove with reference to FIG. 4. Next, the power save operation of eachpower save mode in the image display device 100 according to anembodiment of the present invention will be described.

FIG. 6 is a flowchart illustrating the power save operation when thepower save mode in the image display device 100 according to anembodiment of the present invention is “High.” The power save operationwhen the power save mode in the image display device 100 according to anembodiment of the present invention is “High” will be described belowwith reference to FIG. 6.

First, a timer retained in the image display device 100 is reset inadvance before starting the power save operation (step S121). Forexample, resetting of the timer in step S121 may be executed by theviewing state analysis unit 116.

Subsequently, the viewing state analysis unit 116 executes the facedetection process (step S122). The viewing state analysis unit 116judges whether or not a human face is included in the image transmittedto the image input unit 112 as a result of executing the face detectionprocess through the viewing state analysis unit 116 (step S123).

When the viewing state analysis unit 116 judges that a human face isincluded in the image transmitted to the image input unit 112 in stepS123, the timer retained in the image display device 100 is reset again(step S124). For example, resetting of the timer in step S124 may beexecuted by the viewing state analysis unit 116 similarly to resettingof the timer in step S121.

When the timer is reset in step S124, the system optimization processingunit 120 sets the brightness of the display panel 102 to standardbrightness (brightness at the time of ordinary use) (step S125).

However, when the viewing state analysis unit 116 judges that a humanface is not included in the image transmitted to the image input unit112 in step S123, the system optimization processing unit 120 judgeswhether or not T1 seconds (for example, 10 seconds) have elapsed on thetimer (step S126).

When the system optimization processing unit 120 judges that T1 secondshave elapsed on the timer in step S126, the system optimizationprocessing unit 120 sets the brightness of the display panel 102 to bedark or zero (0) (step S127).

When the system optimization processing unit 120 sets the brightness ofthe display panel 102 to be zero or darkest in step S127 or when thesystem optimization processing unit 120 judges that T1 seconds have notelapsed on the timer yet in step S126, the system optimizationprocessing unit 120 judges whether or not T2 seconds have elapsed on thetimer (here, T2>T1) (step S128).

When the system optimization processing unit 120 judges that T2 secondshave elapsed on the timer in step S128, the system optimizationprocessing unit 120 executes a process of turning main power of theimage display device 100 off (step S129). However, when the systemoptimization processing unit 120 judges that T2 seconds have not elapsedon the timer in step S128, the process returns to step S122, and theface detection process is continued by the viewing state analysis unit116.

The power save operation when the power save mode in the image displaydevice 100 according to an embodiment of the present invention is “High”has been described above with reference to FIG. 6. Next, the power saveoperation when the power save mode in the image display device 100according to an embodiment of the present invention is “Medium” will bedescribed.

FIG. 7 is a flowchart illustrating the power save operation when thepower save mode in the image display device 100 according to anembodiment of the present invention is “Medium.” The power saveoperation when the power save mode in the image display device 100according to an embodiment of the present invention is “Medium” will bedescribed below with reference to FIG. 7.

First, two timers (hereinafter, for convenience of description, the twotimers are referred to as timers 1 and 2, respectively) retained in theimage display device 100 are reset in advance before starting the powersave operation (step S131). For example, resetting of the timers 1 and 2in step S121 may be executed by the viewing state analysis unit 116. Thetimer 1 measures a time in which the viewing state analysis unit 116 hasnot detected the face, and the timer 2 measures a time in which theviewing state analysis unit 116 has not detected the presence of themoving body.

Subsequently, the viewing state analysis unit 116 executes the facedetection process and the moving body detection process (step S132). Theviewing state analysis unit 116 judges whether or not a human face isincluded in the image transmitted to the image input unit 112 as aresult of executing the face detection process through the viewing stateanalysis unit 116 (step S133).

When the viewing state analysis unit 116 judges that a human face isincluded in the image transmitted to the image input unit 112 in stepS133, the timers 1 and 2 retained in the image display device 100 arereset again (step S134). For example, resetting of the timers in stepS134 may be executed by the viewing state analysis unit 116 similarly toresetting of the timers in step S131.

When the timers are reset in step S134, the system optimizationprocessing unit 120 sets the brightness of the display panel 102 tostandard brightness (brightness at the time of ordinary use) (stepS135).

However, when the viewing state analysis unit 116 judges that a humanface is not included in the image transmitted to the image input unit112 in step S133, the viewing state analysis unit 116 judges whether ornot the sensor 106 has detected the moving body (step S136).

When the viewing state analysis unit 116 judges that the sensor 106 hasdetected the moving body in step S136, the timer 2 is reset (step S137).For example, resetting of the timer 2 in step S137 may be executed bythe viewing state analysis unit 116 similarly to resetting of the timersin step S131 and step S134.

When the timer 2 is reset in step S137, it is judged whether or not thebrightness of the display panel 102 is zero (0) (step S138). Forexample, the judgment on the brightness of the display panel 102 may beexecuted by the system optimization processing unit 120.

When the system optimization processing unit 120 judges that thebrightness of the display panel 102 is zero in step S138, the systemoptimization processing unit 120 regards that the user is in front ofthe image display device 100 but the user's face is not facing thedirection of the display panel. Thus, the system optimization processingunit 120 calculates the system control information for performingcontrol to lower the brightness of the display panel 102 and lowers thebrightness of the display panel 102 (step S139).

Subsequently, the system optimization processing unit 120 judges whetheror not T3 seconds (for example, 30 seconds) have elapsed on the timer 1and T4 seconds (for example, 180 seconds), which is longer than T3seconds, have not elapsed on the timer 2 yet (step S140).

When the system optimization processing unit 120 judges whether or notT3 seconds have elapsed on the timer 1 and T4 seconds have not elapsedon the timer 2 yet in step S140, the system optimization processing unit120 regards that the user is in front of the image display device 100but the user's face is not facing the direction of the display panel.Thus, the system optimization processing unit 120 calculates the systemcontrol information for performing control to lower the brightness ofthe display panel 102 and lowers the brightness of the display panel 102(step S141).

However, when the system optimization processing unit 120 judges that T3seconds have not elapsed on the timer 1 yet in step S140, the systemoptimization processing unit 120 skips step S141.

Subsequently, the system optimization processing unit 120 judges whetheror not T4 seconds have elapsed on the timer 2 (step S142). When thesystem optimization processing unit 120 judges that T4 seconds haveelapsed on the timer 2 in step S142, the system optimization processingunit 120 regards that the user is not in front of the image displaydevice 100. Thus, the system optimization processing unit 120 calculatesthe system control information for performing control to bring thebrightness of the display panel 102 to zero and brings the brightness ofthe display panel 102 to zero (step S143).

However, when the system optimization processing unit 120 judges that T4seconds have not elapsed on the timer 2 yet in step S142, the systemoptimization processing unit 120 skips step S142.

Subsequently, the system optimization processing unit 120 judges whetheror not T5 seconds, which is longer than T4 seconds, have elapsed on thetimer 2 (step S144). When the system optimization processing unit 120judges that T5 seconds, which is longer than T4 seconds, have elapsed onthe timer 2 in step S144, the system optimization processing unit 120regards that the user is not in front of the image display device 100.Thus, the system optimization processing unit 120 executes a process ofturning main power of the image display device 100 off (step S145).However, when the system optimization processing unit 120 judges that T5seconds, which is longer than T4 seconds, have not elapsed on the timer2 in step S144, the process returns to step S132, and the face detectionprocess and the moving body detection process are continued by theviewing state analysis unit 116.

The power save operation when the power save mode in the image displaydevice 100 according to an embodiment of the present invention is“Medium” has been described above with reference to FIG. 7. Next, thepower save operation when the power save mode in the image displaydevice 100 according to an embodiment of the present invention is “Low”will be described.

FIG. 8 is a flowchart illustrating the power save operation when thepower save mode in the image display device 100 according to anembodiment of the present invention is “Low.” The power save operationwhen the power save mode in the image display device 100 according to anembodiment of the present invention is “Low” will be described belowwith reference to FIG. 8.

First, a timer retained in the image display device 100 is reset inadvance before starting the power save operation (step S151). Forexample, resetting of the timer in step S151 may be executed by theviewing state analysis unit 116.

Subsequently, the viewing state analysis unit 116 executes the facedetection process and the moving body detection process (step S152). Theviewing state analysis unit 116 judges whether or not the face or themoving body has been detected, that is, a person is in front of theimage display device 100, as a result of executing the face detectionprocess and the moving body detection process through the viewing stateanalysis unit 116 (step S153).

When the viewing state analysis unit 116 judges that the face or themoving body has been detected in step S153, the timer retained in theimage display device 100 is reset again (step S154). For example,resetting of the timer in step S154 may be executed by the viewing stateanalysis unit 116 similarly to resetting of the timer in step S151.

When the timer retained in the image display device 100 is reset in stepS154, the system optimization processing unit 120 sets the brightness ofthe display panel 102 to standard brightness (brightness at the time ofordinary use) (step S155).

However, when the viewing state analysis unit 116 judges that the faceand the moving body have not been detected in step S153, the systemoptimization processing unit 120 judges whether or not T6 seconds (forexample, 600 seconds) have elapsed on the timer (step S156).

When the system optimization processing unit 120 judges that T6 secondshave elapsed on the timer in step S156, the system optimizationprocessing unit 120 sets the brightness of the display panel 102 to bedark or zero (0) (step S157).

When the system optimization processing unit 120 sets the brightness ofthe display panel 102 to be zero or darkest in step S157 or when thesystem optimization processing unit 120 judges that T7 seconds have notelapsed on the timer yet in step S156, the system optimizationprocessing unit 120 judges whether or not T7 seconds have elapsed on thetimer (here, T7>T6) (step S158).

When the system optimization processing unit 120 judges that T7 secondshave elapsed on the timer in step S158, the system optimizationprocessing unit 120 executes a process of turning main power of theimage display device 100 off (step S159). However, when the systemoptimization processing unit 120 judges that T7 seconds have not elapsedon the timer in step S158, the process returns to step S152, and theface detection process and the moving body detection process arecontinued by the viewing state analysis unit 116.

The power save operation when the power save mode in the image displaydevice 100 according to an embodiment of the present invention is “Low”has been described above with reference to FIG. 8.

2. SUMMARY

As described above, according to the image display device 100 accordingto an embodiment of the present invention, it is judged whether the useris in front of the image display device 100 according to whether or nota human face is included in the image captured by the imaging unit 104and whether or not the moving body has been detected by the sensor 106.Since the face detection process and the moving body detection processare combined as described above, the presence of the user who is infront of the image display device 100 can be detected with a high degreeof accuracy.

Further, according to the image display device 100 according to anembodiment of the present invention, a plurality of power save modes canbe implemented by combining the face detection process and the movingbody detection process. That is, the image display device 100 accordingto an embodiment of the present invention can execute the power savemode using only the face detection process and can execute the powersave mode in which the face detection process and the moving bodydetection process are combined. Since a plurality of power save modescan be implemented, it is possible to execute the power save modesuitable for the user's use state of the image display device 100.

Further, a series of processes described above may be implemented byhardware or software. When a series of processes is implemented bysoftware, a program that constitutes the software is installed into acomputer integrated in dedicated hardware or a general-purpose personalcomputer in which a variety of functions can be executed by installing avariety of programs from a program recording medium.

While the preferred embodiments of the present invention have beendescribed above with reference to the accompanying drawings, the presentinvention is of course not limited to the above examples. A personskilled in the art may find various alternations and modificationswithin the scope of the appended claims, and it should be understoodthat they will naturally come under the technical scope of the presentinvention.

For example, the user's use state may be recorded in the image displaydevice 100 in order, and using a result of learning the user's recordeduse state, the system optimization processing unit 120 may automaticallyselect the power save mode from among a plurality of power save modes.An example of an automatic selection process of the power save mode willbe described below.

For example, the user may be specified by performing a face recognitionprocess on an image captured by the imaging unit 104, and the systemoptimization processing unit 120 may automatically select the power savemode for each of the specified users. For example, a power save mode inwhich image erasing is performed less and the power save effect is lowmay previously be set to the image display device 100 for a father, anda power save mode in which image erasing is frequently performed and thepower save effect is low may previously be set to the image displaydevice 100 for a mother. Depending on whether a person included in theimage captured by the imaging unit 104 is the father or the mother, thesystem optimization processing unit 120 may automatically select thepower save mode.

For example, the system optimization processing unit 120 mayautomatically select the optimum power save mode through analysis on aviewing style of a specific individual. For example, in the case of theuser who is more likely to turn on the television for a long time but toview the television less, transition to image erasing is easilyperformed. However, in the case of the user who is more likely to keepviewing a program for a short time, transition to image erasing becomesdifficult to perform. Since it is necessary to record the user's viewingstyle during a specific time period for analysis of the viewing style,automatic setting cannot be used from the beginning, but uponacquisition of necessary data, an automatic setting option can beeffectively used.

Further, for example, a mode may be automatically selected according tocontent that is being viewed through the image display device 100. Forexample, when content such as a movie is viewed through the imagedisplay device 100, continuous viewing may be treated as a priority, anda time until image erasing may increase. When information different fromthe content such commercials is provided at a regular interval, a timeuntil image erasing may increase or decrease in the content part and theother parts. Further, information on content that is being viewedthrough the image display device 100 may be acquired, for example, fromdata of an electronic program guide (EPG) or may be acquired from agenre of the content currently being viewed, and set to the imagedisplay device 100 by the user of the image display device 100.

Further, for example, in view of a situation in which normal imageprocessing cannot be performed due to backlight or shielding or asituation in which a malfunction in which the power save mode startsregardless of whether or not the user views the device occurs, forexample, in an environment in which the user views the device outside anangle of view, the system optimization processing unit 120 may not startthe power save mode even if the face or the moving body is not detecteduntil at least one face is first detected after the power save processstarts.

In order to avoid a malfunction during a time period (or a certain timeperiod thereafter) after the face is detected at least once and theimage display device 100 starts the power save mode, and the user isconsidered to execute an active operation through the remote controller,for example, powering the image display device 100 on or changing thecontent being displayed on the display panel 102, the systemoptimization processing unit 120 may not start the power save mode evenif the face or the moving body is not detected.

Further, in the case in which the power save mode is intentionally beingsuppressed, the image display device 100 may notify the user of asuppression status of the power save mode through a state notificationmeans (for example, an LED or a user interface (UI) indication inside ascreen) included therein. FIGS. 9 and 10 are explanation diagramsillustrating operation examples of the image display device 100 when thepower save mode is intentionally being suppressed. FIG. 9 illustrates anexample in which an LED 109 emits light of predetermined color as anindicator representing that the power save mode is being suppressed whenthe power save mode is intentionally being suppressed. FIG. 10illustrates an example in which a graphical user interface (GUI)indicator 103 representing that the power save mode is being suppressedis displayed on the display panel 102 when the power save mode isintentionally being suppressed.

REFERENCE SIGNS LIST

-   100 image display device-   102 display panel-   104 imaging unit-   106 sensor-   108 speaker-   109 LED-   110 control unit-   112 image input unit-   114 image processing unit-   116 viewing state analysis unit-   118 viewing state recording unit-   120 system optimization processing unit-   122 system control unit-   132 user viewing state analysis unit-   134 user motion analysis unit-   142 panel optimization processing calculation unit-   144 speaker optimization processing calculation unit-   152 optimization processing effect calculation unit

The invention claimed is:
 1. A display device, comprising: a circuitconnected to a first sensor to receive a moving image captured by thefirst sensor in a predetermined range and connected to a second sensorto detect whether a moving body is present in the image displaydirection, the circuitry being configured to analyze the moving image todetect whether or not a face is present, and after power is turned on,start to control power consumption with different patterns according toa plurality of modes when the face is present in the moving image or themoving body is present in the display direction, wherein the differentpatterns include a first pattern in which power consumption is rampeddown in at least two decreasing stages and ramped up in at least twoincreasing stages based on detection of the face and the moving body,when power consumption is ramped down, a first of the at least twodecreasing stages is reached based on lack of detection of the face anda second of the at least two decreasing stages is reached based on lackof detection of the moving body, and when power consumption is rampedup, a first of the at least two increasing stages is reached based ondetection of the moving body, the first of the at least to increasingstages being reached by increasing brightness, the power consumptionremaining at the first of the at least two stages until detection of theface, the power consumption being increased from the first state to fullpower upon detection of the face.
 2. The display device according toclaim 1, wherein the power consumption is controlled according to asecond pattern based only on whether or not the face is present, andwhen the circuit does not detect the presence of the face during apredetermined time, power consumption decreases.
 3. The display deviceaccording to claim 1, wherein power consumption is controlled accordingto a third pattern based on whether or not the face is present andwhether or not the moving body is present, and when the circuit does notdetect the face during a predetermined time and the second sensor doesnot detect the moving body during the predetermined time, powerconsumption decreases.
 4. The display device according to claim 1,wherein the circuit controls power consumption by increasing ordecreasing brightness of a display panel that displays an image.
 5. Thedisplay device according to claim 1, wherein the circuit controls powerconsumption by increasing or decreasing a sound volume of a speaker thatplays a voice.
 6. The display device according to claim 1, wherein thecircuit controls power consumption by controlling an operation of acircuit configured to increase an image quality of a display image. 7.The display device according to claim 1, wherein the circuit is furtherconfigured to notify that control of power consumption is stopped whenthe circuit stops control of power consumption.
 8. The display deviceaccording to claim 1, wherein the circuit specifies an individualthrough analysis on the moving image, and the circuit automaticallyselects a mode corresponding to the individual specified.
 9. The displaydevice according to claim 1, wherein the circuit automatically selects amode corresponding to details of content to be displayed.
 10. Thedisplay device according to claim 1, wherein the second sensor isfurther configured to determine a distance between the display deviceand the moving body.
 11. The display device according to claim 10,wherein the circuit is configured to exclude a moving body as adetection target when the distance between the display device and themoving body as determined by the second sensor is more than apredetermined distance.
 12. A display device, comprising: a sensorconfigured to detect whether or not a moving body is present in apredetermined range in an image display direction; and circuitryconfigured to analyze a moving image captured in a predetermined rangein the image display direction, to detect whether or not a face ispresent, and after power is turned on, start control power consumptionwith different patterns according to a plurality of modes when the faceis present in the moving image or the moving body is present in thepredetermined range in the display direction, wherein the differentpatterns include a first pattern in which power consumption is rampeddown in at least two decreasing stages and ramped up in at least twoincreasing stages based on detection of the face and the moving body,when power consumption is ramped down, a first of the at least twodecreasing stages is reached based on lack of detection of the face anda second of the at least two decreasing stages is reached based on lackof detection of the moving body, and when power consumption is rampedup, a first of the at least two increasing stages is reached based ondetection of the moving body, the first of the at least two increasingstages being reached by increasing brightness, the power consumptionremaining at the first of the at least two stages until detection of theface, the power consumption being increased from the first state to fullpower upon detection of the face.
 13. A control method, comprising:analyzing a moving image captured in a predetermined range in an imagedisplay direction by a first sensor to detect whether or not a face ispresent; detecting, via a second sensor and separately from capturedmoving images, whether or not a moving body is present in thepredetermined range in the image display direction; and after power isturned on, starting control of power consumption with different patternsaccording to a plurality of modes when the face is present in the movingimage or when the moving body is present in the display direction,wherein the different patterns include a first pattern in which powerconsumption is ramped down in at least two decreasing stages and rampedup in at least two increasing stages based on detection of the face andthe moving body, when power consumption is ramped down, a first of theat least two decreasing stages is reached based on lack of detection ofthe face and a second of the at least two decreasing stages is reachedbased on lack of detection of the moving body, and when powerconsumption is ramped up, a first of the at least two increasing stagesis reached based on detection of the moving body, the first of the atleast two increasing stages being reached by increasing brightness, thepower consumption remaining at the first of the at least two stagesuntil detection of the face, the power consumption being increased fromthe first state to full power upon detection of the face.
 14. Thecontrol method of claim 13, further comprising: determining, by thesecond sensor, a distance between the second sensor and the moving body.15. The control method of claim 14, further comprising: excluding amoving body as a detection target when the second sensor determines themoving body to be more than a predetermined distance from the secondsensor in the display direction.